In a first conventional automotive alternator, notches that have L-shaped cross sections for interfitting are formed by cutting, etc., on outer circumferential portions of two axial end surfaces of a cylindrical stator core so as to have ring shapes. A pair of bowl-shaped frames is fitted together with the notches on the stator core in a press-fitted state from two axial ends such that the stator is interlocked in the pair of frames (see Patent Literature 1, for example).
In a second conventional automotive alternator, a stator core is prepared into a cylindrical shape by coiling up and laminating a strip-shaped steel plate into a helical shape. A groove-shaped recess portion that extends axially is disposed on an outer circumferential portion of the stator core. Two axial end surfaces of the stator core are formed so as to have flat surfaces. A pair of bowl-shaped frames is placed on the two axial end surfaces of the stator core from two axial ends, and are fastened using a through bolt that is disposed in the recess portion. Thus, the stator core is pressed and held by the pair of frames from the two axial ends (see Patent Literature 2, for example).    Patent Literature 1: Japanese Utility Model Non-Examined Publication No. SHO 62-88442 (Gazette)    Patent Literature 2: Japanese Patent Laid-Open No. 2002-186232 (Gazette)